Writing instruments



April 30, 1963 D. KAHN ETAI.

WRITING INSTRUMENTS Filed Feb. is, 1959 2 Sheets-Sheet 1 FIG.1

F I :41 //fi// April 30, 1963 D. KAHN 51 Al. 3,087,463

I WRITING INSTRUMENTS Filed Feb. 13, 1959 2 Sheets-Sheet 2 United States Patent 3,087,463 WRITING INSTRUMENTS David Kahn, deceased, late of Englewood Cliffs, N.J., by

Julius M. Kahn, Samuel Kahn, and Harry Yager, executors, all of Englewood Cliffs, N.J.; and Karl Weisser, deceased, late of Cresskiil, N.J., by Helen E. Weisser, executrix, Cresskill, N .J., assignors to David Kahn, Inc., North Bergen, N.J., a corporation of New Jersey Filed Feb. 13, 1959, Ser. No. 793,071 16 Claims. (Cl. 12045.4)

The present invention relates to writing instruments and more particularly to the provision of an ink cartridge which can be more easily and securely assembled and which upon insertion into a appropriately formed Writing instrument will automatically produce a selfpriming action to prepare the writing instrument for immediate use.

This application is a continuation-in-part of application Serial No. 619,585 filed October 31, 1956 now abondoned.

The present invention constitutes an improvement over the replaceable cartridge containing writing instrument described in the copending application of Julius M. Kahn and Morris Levy, Serial No. 576,357, filed April 5, 1956, now Patent No. 2,964,012, granted December 13, 1960, and the present invention is particularly adapted for use in the writing instrument disclosed therein after the ink cartridge and barrel of the said copending application are modified in accordance with the present invention.

The present invention has as its primary purpose and object to provide an ink cartridge and a cartridge-writing instrument combination in which the cartridge is of simplified and unitary construction while enabling some of the ink in the cartridge to be automatically discharged when the cartridge is replaced so that, when the writing instrument is reassembled and without precaution or additional operation, the empty instrument in which the fresh cartridge is inserted will be primed with fresh ink for immediate use.

More particularly, the present invention includes an openable or pierceable closure on the forward end of a filled tubular holder for ink and also includes a holder and barrel construction which permits the mere screwing home of the pen assembly unit shown in the above mentioned copending application to result in the automatic priming of the writing instrument.

The invent-ion includes the provision of an ink-cartridge, as aforesaid, said cartridge being structurally adapted for rapid and efficient assembly to provide a nonleaking and unitary cartridge unit.

In accordance with the present invention, the rear end of the cartridge is formed with a rearwardly extending deformable bulged portion, which is preferably thin so that it can be easily deformed, and this bulged portion cooperates with a deforming member which is positioned at the rear of the cartridge receiving chamber in the barrel. As a result of this novel structure, when the fresh cartridge is forced into the barrel during the assembling or re-assembling of the writing instrument, the bulged rear end of the cartridge is forced against the deforming member and is deformed thereby to increase the pressure within the cartridge and thereby force some of the ink out of the pierced or opened forward extremity of the cartridge to prime the writing instrument.

The new ink cartridge also includes an improved nonleakable seal in which a metal ferrule or collar is crimped about aligned abutting circular shoulders on the forward end of the cartridge. These shoulders are constituted by a circumferential outwardly extending flange at the forward end of the tubular in-holder which abuts an outwardly extending circumferential flange on the closure or 3,087,463 Patented Apr. 30, 1963 plug member which seals the forward open end of the tubular holder.

As a modification, the new ink cartridge also includes a non-leakable assembly in which the pierceable or openable partition is formed integral with the tubular body of the cartridge and the open rear end of the tubular body or ink-holder is closed by a plug including a bulged portion, a circumferential flange and an annular sealing projection extending forwardly of the circumferential flange and positioned inwardly of the outer periphery thereof. The plug may be adhesively secured in position or it may be secured in position by means of a ferrule or collar.

The invention will now be more fully described in conjunction with the accompanying drawing in which:

FIG. 1 is a sectional elevational view showing a tubular holder of an ink cartridge constructed in accordance with the invention.

FIG. 2 is a sectional elevational view showing a closure member for closing the open forward extremity of the tubular holder of FIG. 1.

FIG. 3 is a sectional elevational view of a metal ferrule prior to insertion thereof upon the tubular body of the ink cartridge.

FIG. 4 is a partial sectional elevational view showing the closure member of FIG. 2 inserted into the open forward forward extremity of the tubular holder of FIG. 1 and with the ferrule of FIG. 3 in assembled position prior to final crimping of the ferrule.

FIG. 5 is a sectional elevational view showing the filled and completed ink cartridge after the ferrule has been crimped to seal the closure member to the tubular holder.

FIG. 6 is a partial sectional elevational view showing the rear of the barrel of a writing instrument constructed in accordance with the invention with an ink cartridge inserted therein, said cartridge being shown prior to the final assembly of the writing instrument at which point the automatic priming action of the invention takes place.

FIG. 7 is a sectional elevational view of the complete barrel of FIG. 6 with the pen section threaded home therein to fully insert the cartridge in the barrel and achieve the automatic priming action of the invention.

FIG. 8 is an exploded sectional view of a modified form of link cartridge constructed in accordance with the invention.

FIG. 9 is an exploded view of a modified form of the ink cartridge showing the cartridge in the process of assembly.

FIG. 10 is a vertical view of the assembled cartridge of FIG. 9.

FIG. 11 is a sectional vertical view showing the filled and completed ink cartridge of FIGS. 9 and 10.

FIG. '12 is a rear end view of the feed bar of FIG. 7 prior to insertion of the feed bar in the pen section.

Referring more particularly to the drawings, the tubular ink holder shown in FIG. 1 is generically denoted by the numeral 20 and is constituted by a tubular body 21 having a circumferential outwardly extending flange 22 at the forward end thereof. The flange 22 is preferably undercut as indicated at 23. The rear end of the tubular ink holder 20 is closed by means of a deformable rearwardly extending bulged integral bottom portion 24. The ink holder 20 is preferably molded in a single piece with the flange 22 and the bulged portion 24 being formed integral with the tubular body 21. The tubular body 21 is preferably of sufiicient thickness to be reasonably rigid, e.g. dimensionally stable.

The bulged portion 24 is preferably formed thinner than the body portion 21 to facilitate the ease of deforming this bulged portion. However, it is not essential that the bulged portion 24 be thinner than the body portion 21 since reasonable dimensional stability of the ink holder 20 may be achieved with walls of sufficient flexibility to permit their being deformed by a vigorously applied force exerted by a reasonably sharp instrumentality.

Referring to FIG. 2, the closure member or plug 26 is tubular and is provided with a centrally disposed outwardly extending circumferential flange 26'. The inner portion of the tubular closure or plug 26 is bridged by a partition 27 which, .as shown in FIG. 2, is preferably thinner at the peripheral margins thereof to facilitate puncturing of the same, e.g. severing or opening of the portion 27 by means of a cylindrical piercing member. The partition 27 is positioned to the rear of the forward extremity of the closing plug 26 to provide an annular guide portion 27'. The flange 26 is forwardly positioned along the length of the closing plug 26 to provide a circumferential wall 26" for insertion in the forward open extremity of the ink holder 26).

FIG. 3 shows a tubular metal ferrule '28 which is provided with an inwardly crimped portion 29 at one end thereof. As can be seen in FIG. 4, theferrule 28 is slipped over the ink holder 20 from the rearward end thereof and is moved upwardly until the crimped portion 29 engages the circumferential flange 22 of the ink holder 20. As will be observed with reference to FIG. 1, the crimped portion 29 preferably extends into the undercut portion 23. As is also shown in FIG. 4, the crimped portion 29 of the ferrule 28 extends toward the rear of the ink holder 20.

After the ink holder 20 has been filled with liquid writing fluid, e.g. ink, the plug or closure member 26 is inserted into the open forward end of the body portion 21 until the circumferential flange 26 of the plug or closure member 26 is in firm engagement with the circumferential flange 22 at the open forward extremity of the ink holder 20.

Referring now to FIG. 5, the upper end of the ferrule 28 is crimped over upon the abutting circumferential flanges 22 and 26' to form the crimped portion 29 which finally seals the completed ink holder 24) to form the completed ink cartridge.

Referring to FIG. 6, the rear of the ink holder 20 is shown inserted within the tubular barrel of a writing instrument, e.g. a fountain pen. It will be observed that a deforming member 16 has been secured toward the rear of the barrel 10, the deforming member 16 being provided with a centrally disposed forwardly projecting deforming protuberance 17. This protuberance 17 engages the bulged portion 24 of the ink holder 20 and prevents the full insertion of the ink cartridge into the barrel 10. The deforming member 16 is preferably bored, as indicated at 18, to facilitate insertion and removal of the ink cartridge.

FIG. 7 shows a completed writing instrument constructed in accordance with the invention, the details of this writing instrument being more fully discussed in the aforementioned copending application.

Referring more particularly to P16. 7, the ink holder 20 is shown fully inserted Within the barrel 10 with the bulged portion 24 of the holder 20 forced against and deformed by the deforming protuberance 17 of the deforming member 16. As will be seen, the deforming member 16 is secured within the barrel 10 against an abutting shuolder 11 which constitutes the rear of a cartridge receiving chamber which communicates with the open forward extremity of the barrel. The deforming member 16 may be glued in place.

The exterior of the forward portion of the barrel is provided with a threaded portion 12 to which a conventional cap (not shown) can be secured and the interior of the forward portion of the barrel is provided with a threaded portion 13 to which a pen section 30 is secured by means of the external threads 31 which are formed thereon. The rear of the barrel is vented by the bore 14a in plug 14.

Referring again to FIG. 5, the forward end of the ink cartridge is rimmed by the ferrule 28 which constitutes, together with the supporting circumferential flange 22 and 26, an external outwardly extending circumferential rib 25 and, as shown in FIG. 7, the interior of the barrel 10 is formed with a shoulder 15 positioned near the forward extremity thereof. Shoulder 15 is dimensioned to permit passages of the ink holder body portion 21 while preventing passage of the rib 25. Accordingly, the ink cartridge cannot be improperly inserted in the barrel 10.

Fitted within the pen section 30 is a feed bar 40 and a pen nib 50 is interposed between the pen section 36 and the feed bar 40. The feed bar 40 includes a semi-cylindrical (see FIG. 12) rearward extension 42. The feed bar 40 is provided with a plurality of longitudinal grooves 48.

Referring more particularly to the pen section 30, this pen section is symmetrically formed about the central longitudinal axis 37 of the writing instrument. The pen section 30 includes a rear portion 33 of reduced diameter, the exterior of which is threaded at 31. The numeral 35 designates the tubular piercing extension within which is fitted the rearward extension 42 of the feed bar 40. The numeral 41 generically denotes an ink feed channel extending between the feed bar 40 and the interior of the pen section 30 and communicating between the lower end of the piercing extension 35 and the pen nib 50 to permit ink in the ink cartridge to flow to the nib 50 for use in writing. The longitudinal grooves 48a form part of the ink feed channel.

The pen section 30 with the feed bar 40 and the pen nib 50 constitute a unitary assembly which is connected with the barrel 10 by screwing home this unitary assembly utilizing the threads 31 in conjunction with the threads 13 on the interior of the barrel.

As the unitary assembly above referred to is screwed home upon the barrel 10, the piercing extension 35 engages the partition 27 of the plug or closure member 26 and forces the cartridge rearwardly in the barrel 10 to urge the bulged portion 24 against the protuberance 17. Finally, the extension 35 pierces the partition 27 and the extension 35 moves rearwardly through the interior of plug 26 until the rear face 33a of the reduced portion 33 of the pen section 30 bears against the forward extremity of the ink cartridge, e.g. the plug 26. When the assembly is now fully threaded home, the bulged portion 24 is forced against the protuberance 17 which forces the por- 24 to deform into substantially the shape shown in As will be appreciated, the deformation above referred to occurs while the extension 35 is immersed in the ink with the ink cartridge in sealing relation with the pen section. This reduces the volume of the cartridge while the cartridge is sealed and raises the pressure therein. More particularly, the extension 35 is in sealing engagement with the annular guide 27' of the plug 26. As a result, the pressure in the ink cartridge is increased and a small .amount of ink is forced out of the cartridge through the ink feed chamber 41 where it reaches the nib 50 to permit substantially immediate writing. The presence of the annular guide 27' thus contributes to the achievement of an effective self-priming action.

As can be seen in FIG. 8, a tubular ink holder 20' is provided with the upper end thereof closed by means of an integrally formed openable or pierceable partition 27". There is also formed integrally with the ink holder 20, a circumferential flange 25 and an annular guide for the tubular extension 35, said annular guide being designated by the numeral 27".

The lower open end of the ink holder 20' is closed by means of a closing plug 51, the closing plug 51 including a bulged portion 52, the rearwardmost portion of the bulged portion having a central thickened reinforcing portion 52a. The forward end of the closing plug 51 is formed with an outwardly extending circumferential flange 53 which is provided with an abutting shoulder 54, the shoulder 54 bearing against the lower extremity of the tubular ink holder 20 when the closing plug 51 is insen-ted therein. The closing plug 51 also includes a forwardly projecting annular sealing projection 55 which bears against the interior of the lower extremity of the tubular ink holder 20'. In this manner, a large surface area is provided between the closing plug '51 and the lower extremity of the tubular ink holder 20'. When this large surface area is present, the liquid writing fluid is effectively trapped Within the ink cartridge and when the closing plug 51 is secured to the tubular ink holder 20" either by the application of adhesive to the shoulder 54 and/or the exterior of the annular projection 55, or by the application of heat and pressure to seal the shoulder 54 to the lower extremity of the tubular ink holder 20, an effective and non-leaking construction is simply and quickly attained.

In FIGS. 9, and 11 there is shown another modification of the ink cartridge of FIG. '8. According to this modification, a tubular ink holder 60 is provided with the upper end thereof closed by means of integrally formed openable or pierceable partitions 61. The bore of the ink holder above the partition 61 has a reduced diameter to define an annular guide 62 for the tubular extension 35.

The lower end of the ink holder 60 is closed by means of a closing plug 64, the latter including a rearwardly extending bulged portion 68, the rear of the bulged portion having a thickened portion 69 for reinforcing the bulged portion. The forward end of the closing plug 64 is formed with an outwardly extending circumferential flange 66 which is provided with an abutting shoulder 67, the shoulder '67 bearing against the lower extremity of the tubular ink holder 60 when the closing plug 64 is inserted therein. The closing plug 64 also includes a forwardly projecting annular projection 65 which bears against the interior of the lower extremity of the tubular ink holder 60.

Preferably, the forward end 74 of the annular projection 65 tapers inwardly in order to permit the plug 64 to be easily inserted into the lower open end of the ink holder 60. The insertion of the plug may also be facilitated by providing the lower end of the ink holder 60 with an enlarged radial recess 75.

In assembling the cartridge of FIGS. 9-11, the ink 63 and the ball B are inserted in the ink holder 60 and the plug 64 is then inserted into the lower open end of the ink holder 60. In the modification shown in FIG. 8, the plug is secured in position by an adhesive or heat-sealing. If desired, adhesive bonding or heat-sealing may be used in the modification of FIGS. 9-l1. However, whether or not such sealing means are used in FIGS. 9-11, there is used a ferrule 70 which is provided with an inwardly turned flange 71 at the lower end. After the plug is placed into the lower end of the ink holder 60, the ferrule 70 is placed into position as shown in FIG. 11 and the forward end of the ferrule is reduced in diameter as shown at 72 by crimping or in any other manner.

Reduction of the diameter of the forward end of the ferrule also pinches inwardly the abutting portion of the ink holder as shown at 72. This serves to secure the ferrule and, therefore, the plug to the cartridge. The flange 71 abuts the lower surf-ace of the circumferential flange 53.

The ferrule 70 may be made of any desirable material but is preferably made of metal. By utilizing the ferrule, it is not necessary to adhesively bond the plug to the ink holder. When a cartridge is made in accordance with the structure of FIG. 8 utilizing heat-sealing, there is a tendency for the adhesive seal to break during freezing weather because of the expansion of the ink in the cartridge. The utilization of the metal ferrule eliminates the possibility of separation of the plug when the contents of the cartridge are frozen. The tightening or crimping of the ferrule at 71 forces the cartridge into secure engagement with the projection 65 of the plug and prevents leakage of ink from the cartridge.

If desired, the cartridge of FIG. 11 may be provided with a circumferential flange at the upper end thereof similar to that shown at 25' in FIG. 8. On the other band, if desired the flange 25' may be eliminated from the modification of FIG. 8. It is evident that the ink holder and plug of FIG. 11 may be utilized without the ferrule, the plug being secured in the ink holder in the same manner as the plug of FIG. 8.

The ink cartridges of FIGS. 8-11 operate in the identical manner as the ink cartridge of FIG. 5, the bulged portions 52 or 68 being deformed by the deforming member 16 in the same manner as the bulged portion 24 of the ink cartridge of FIG. 5.

Thus, it can be seen that in the illustrated embodiments there is provided a deformable bulged portion, the bulged portion being generally concavo-convex with its external diameter not exceeding the internal diameter of the tubular ink holder.

Unlike prior art writing instruments utilizing replaceable ink cartridge units, it is not necesary to shake the pen in order to force the ink to flow when the cartridge is initially inserted. Instead, mere insertion and assembly produces an automatic priming action.

Other means, such as are disclosed in the aforesaid copending application, may be used in the ink cartridge to still further facilitate the flow of ink from the cartridge by breaking any vapor barrier which may exist at the rear of the extension 35, said means including a ball B.

If the writing instrument should be left open, e.g. with the cap removed, for a prolonged period with the instrument positioned so that the ink in the cartridge does not contact the feeding extension, the writing fluid may dry in the pen section. In accordance with the invention, the bulged portion 24 is preferably resilient so that, upon loosening the pen section 30, the bulged portion 24 will expand to draw air into the cartridge through the ink feed channel 41 which is open because of the evaporation of ink. The pen can now be placed in writing position and the pen section screwed home to employ the bulged portion 24 as a pump to prime the pen should this become necessary between cartridge replacements. This pumping action is facilitated by the presence of the annular guide 27' in sealing engagement with the extension 35 since this permits loosening of pen section '30 without danger of leakage.

-It is apparent that the rear face 33a of the reduced portion 33 of the pen section 30 defines a stop surface which limits the telescoping or insertion of the extension 35 into the ink cartridge. Therefore, when the pen is completely assembled and the pen section is fully seated in the open end of the barrel, the distance between the rear face or stop surface 33a and the forward extremity of protuberance 17 will be less than the total length of the cartridge. As a result of this, as the pen section 30 is being screwed into the barrel, the bulged portion of the cartridge will be forced against the protuberance which will cause the bulged portion to deform to force a small amount of writ ing fluid out of the cartridge into the ink feed section.

Because of the axial rigidity or stiffness of the body portion of the cartridge, only the bulged portion will be deformed.

In all the described embodiments of the present invention, the rear end portion of the cartridge is immovably secured to the body of the cartridge either by being made integral therewith or by reason of adhesive engagement or by use of a ferrule.

Attention is directed to FIG. 7 which shows the partition of the cartridge in the open position. The diameter of the annular guide at the forward end of the cartridge and the diameter of the rear extension 3-5 of the pen unit, are both smaller than the diameter of the body of the cartridge immediately below the openable partition. Because of this construction, when the rear extension 35 is inserted into the annular guide, the partition is forced rearwardly but remains fastened to the cartridge in a hinge-like manner. In other words, there is sufficient clearance between the outer periphery of the rear extension 35 and the inner diameter of the body of the cartridge to permit the partition to remain secured to the cartridge. This construction prevents the partition from falling free into the ink supply and possibly blocking the passage of ink.

In the constructions of both FIG. 8 and FIG. 11, the external diameter of projections 55 and 65 respectively may be slightly greater than the internal diameter of the lower portion of the cartridge body so that when the plug is inserted in the body, the diameter of the contiguous portions of the body will be slightly increased. This assists in providing a firm liquid-tight seal. The use of the ferrule as shown in FIG. 12 further serves to tighten the connection between the sealing projection and the lower end of the body.

What is claimed is:

1. A writing instrument comprising a barrel having an open forward extremity, a replaceable rigid cartridge containing liquid writing fluid, said cartridge being slidably positioned within said barrel, said cartridge having a closed rear end portion constituted by a deformable rearwardly extending bulged portion, said bulged portion defining a relatively small portion of the volume of said cartridge, deforming means immovably positioned within said barrel and limiting the rearward movement of said cartridge within said barrel, a pen section secured to the open forward extremity of said barrel, said pen section having a rearwardly extending ink feed section, said ink feed section extending into said cartridge, said cartridge being normally separable from said ink feed section, said pen section engaging said cartridge and forcing the rear of said cartridge against said deforming means whereby said bulged portion is deformed and forced inwardly of said cartridge to slightly reduce the volume of said cartridge and to force only a small amount of the writing fluid out of said cartridge into said ink feed section.

2. A writing instrument comprising a tubular barrel having an open forward extremity communicating with a cartridge receiving chamber within said barrel, deforming means immovably positioned within said barrel at the rear of said cartridge receiving chamber, a replaceable rigid cartridge containing liquid writing fluid, said cartridge being slidably positioned within said cartridge receiving chamber with the rear end of said cartridge terminating in a rearwardly extending bulged portion, said bulged portion defining a relatively small portion of the volume of said cartridge, said deforming means engaging said bulged portion and limiting the rearward movement of said cartridge within said barrel, a pen section secured to the open forward extremity of said barrel, said pen section having a rearwardly extending ink feed section extending into said cartridge, said cartridge being normally separable from said ink feed section, said pen section engaging said cartridge and forcing the rear of said cartridge against said deforming means whereby said bulged portion is deformed and forced inwardly of said cartridge to slightly reduce the volume of said cartridge and to force only a small amount of the writing fluid out of said cartridge into said ink feed section.

3. A writing instrument as recited in claim 2 in which said ink car-tridge is provided with a forward annular guide portion with an openable partition positioned therebehind, said ink feed section extending through said annular guide in sealing engagement therewith.

4. A writing instrument as recited in claim 2 wherein said ink cartridge comprises an elongated tubular body having a central opening therethrough, an openable partition intermediate the ends of said opening, said partition being positioned near the forward end of said cartridge,

the forward end of said opening defining a forward annular guide portion for reception of said ink feed section, the rearwardly extending bulged portion closing the rear end of said opening, said ink feed section extending through said annular guide in sealing engagement therewith, the forward portion of said cartridge having an outwardly extending circumferential flange, the forward extremity of said barrel having a diameter at least equal to the diameter of said flange, said barrel having a shoulder of a diameter less than that of said flange rearward of said flange.

5. A writing instrument as recited in claim 1 wherein said bulged portion is generally concavo-convex.

6. A writing instrument as recited in claim 5 wherein the external diameter of said bulged portion does not exceed the internal diameter of said cartridge.

7. A writing instrument comprising a tubular barrel having an open forward extremity communicating with a cartridge receiving chamber within said barrel, deforming means immovably positioned within said barrel at the rear of said cartridge receiving chamber, said deforming means having a centrally located forwardly extending protuberance positioned thereon, a replaceable rigid cartridge containing liquid writing fluid, said cartridge being slidably positioned within said cartridge receivng chamber with the rear end of said cartridge terminating in a rearwardly extending bulged portion, said bulged portion defining a relatively small portion of the volume of said cartridge, said deforming means engaging the rear of said cartridge to limit the rearward movement of said cartridge within said barrel, a pen section threadedly secured to the open forward extremity of said barrel, said pen section having a rearwardly extending tubular ink feed section, said ink cartridge having a forward annular guide portion with an openable partition positioned therebehind, said ink feed section being fitted within said annular guide and sealingly engaging the same and extending into said cartridge, said cartridge being normally separable from said ink feed section, said pen section engaging said cartridge and forcing said bulged portion against said protuberance to deform said bulged portion inwardly of said cartridge to slightly reduce the volume of said cartridge and to force only a small amount of the writing fluid out of said cartridge into said ink feed section.

8. An ink cartridge comprising a rigid elongated straight-walled tubular body having a longitudinal opening therethrough, a small rear end portion immovably secured to and closing one end of said body, said rear end portion being constituted by a deformable rearwardly extending generally concavo-convex bulged portion, said bulged portion defining a relatively small portion of the volume of said cartridge, an openable partition obstructing said longitudinal opening near the forward end of said cartridge, said partition being positioned rearward of the forward extremity of said opening, whereby the forward extremity of said opening defines an annular guide for reception of an ink feed section of a pen section, and liquid wiriting fluid in said cartridge, said partition preventing egress of writing fluid from said cartridge, said rear end portion comprising a closed plug fitted within the rear end of the opening in said tubular body, said plug having a deformable rearwardly projecting generally concave-convex bulged portion, a circumferential flange forward of said bulged portion, the diameter of said flange being substantially equal to the external diameter of the rear of said body, an annular sealing projection extending forwardly of said circumferential flange and positioned inwardly of the outer periphery of said flange, said projection extending within the open rearward extremity of said body.

.9. An ink cartridge as recited in claim 8 wherein the external diameter of said bulged portion does not exceed the internal diameter of said tubular ink holder.

10. An ink cartridge as recited in claim 9 wherein the forward extremity of said ink cartridge is provided with an outwardly extending circumferential flange immovable relative to said body, the diameter of said flange being greater than the diameter of said cartridge rearward of said flange.

11. An ink cartridge comprising a rigid elongated straight-walled tubular body having a longitudinal opening therethrough, a small rear end portion immovably secured to and closing one end of said body, said rear end portion being constituted by a deformable rearwardly extending generally concave-convex bulged portion, said bulged portion defining a realtively small portion of the volume of said cartridge, an openable partition obstructing said longitudinal opening near the forward end of said cartridge, said partition being positioned rearward of the forward extremity of said opening, whereby the forward extremity of said opening defines an annular guide for reception of an ink feed section of a pen section, and liquid writing fluid in said cartridge, said partition preventing egress of writing fluid from said cartridge, the forward extremity of said ink cartridge being provided with an outwardly extending circumferential flange, the flange immovable relative to said body, the diameter of said flange being greater than the diameter of said cartridge rearward of said flange, the rearward extremity of said bulged portion being reinforced.

12. An ink cartridge comprising a rigid elongated straight-walled tubular body having a longitudinal opening therethrough, a small rear end portion immovably secured to and closing one end of said body, said rear end portion comprising a closed plug fitted Within the rear end of the opening in said tubular body, said plug having a deformable rearwardly projecting generally concavo-convex bulged portion, said bulged portion defining a relatively small portion of the volume of said cartridge, an openable partition obstructing said longitudinal opening near the forward end of said cartridge, said partition being positioned rearward of the forward extremity of said opening, whereby the forward extremity of said opening defines an annular guide for reception of an ink feed section of a pen section, and writing fluid in said cartridge, said partition preventing egress of writing fluid from said cartridge, said plug having a circumferential flange forward of said bulged portion, the diameter of said flange being substantially equal to the external diameter of the rear of said body, an annular sealing projection extending forwardly of said circumferential flange and positioned inwardly of the outer periphery of said flange, said projection extending within the open rearward extremity of said body, said plug being secured to said body by a ferrule surrounding said circumferential flange and the rear extremity of said body.

13. An ink cartridge as recited in claim 12 wherein the forward end of said ferrule has a reduced diameter whereby the abutting portion of the body is maintained it) in secure sealing engagement with said sealing projection.

14. An ink cartridge comprising a rigid elongated straight walled plastic tubular body formed with an integral closed rear end portion constituted by a thin deformable rearwardly extending bulged portion and an open forward extremity, the open forward extremity of said tubular body being provided with an integral outwardly extending circumferential flange, a plastic closing plug, said plug having a forward annular guide portion, a centrally disposed openable partition positioned rearwardly of said guide portion, an outwardly extending circumferential flange and a circumferential wall positioned rearwardly of the flange of said plug, said plug being fixedly secured to said tubular body with the said wall of said plug fitted within the open forward extremity of said tubular body and with the said flange of said plug abutting the said flange of said tubular body.

15. A writing instrument as recited in claim 1 wherein said rear end portion comprises a closed plug fitted within the rear end of the body of said cartridge, said plug having a deformable rearwardly projecting generally concavoconvex bulged portion.

16. An ink cartridge comprising a rigid elongated straight-walled tubular body having a longitudinal opening therethrough, a small rear end portion immovably secured to and closing one end of said body, said rear end portion being constituted by a deformable rearwardly extending generally concavo-convex bulged portion, said bulged portion defining a relatively small portion of the volume of said cartridge, an openable partition obstructing said longitudinal opening near the forward end of said cartridge, said partition being positioned rearward of the forward extremity of said opening, whereby the forward extremity of said opening defines an annular guide for reception of an ink feed section of a pen section, and liquid wiriting fluid in said cartridge, said partition preventing egress of writing fluid from said cartridge, the forward end of said body being closed by means of a closing plug fixedly secured thereto, said plug including said openable partition, the forward end of said body being provided with an outwardly extending circumferential flange, said plug having an outwardly extending circumferential flange abutting the flange of said body, said plug being secured to the body in a fluid tight manner by a metal ferrule crimped around said abutting flanges.

References Cited in the file of this patent UNITED STATES PATENTS 1,765,383 Punte June 24, 1930 2,870,742 Hackmeyer Jan. 27, 1959 FOREIGN PATENTS 45,768 .Germany June 14, 1888 269,681 Switzerland July 15, 1950 

1. A WRITING INSTRUMENT COMPRISING A BARREL HAVING AN OPEN FORWARD EXTREMITY, A REPLACEABLE RIGID CARTRIDGE CONTAINING LIQUID WRITING FLUID, SAID CARTRIDGE BEING SLIDABLY POSITIONED WITHIN SAID BARREL, SAID CARTRIDGE HAVING A CLOSED REAR END PORTION CONSTITUTED BY A DEFORMABLE REARWARDLY EXTENDING BULGED PORTION, SAID BULGED PORTION DEFINING A RELATIVELY SMALL PORTION OF THE VOLUME OF SAID CARTRIDGE, DEFORMING MEANS IMMOVABLY POSITIONED WITHIN SAID BARREL AND LIMITING THE REARWARD MOVEMENT OF SAID CARTRIDGE WITHIN SAID BARREL, A PEN SECTION SECURED TO THE OPEN FORWARD EXTREMITY OF SAID BARREL, SAID PEN SECTION HAVING A REARWARDLY EXTENDING INK FEED SECTION, SAID INK FEED SECTION EXTENDING INTO SAID CARTRIDGE, SAID CARTRIDGE BEING NORMALLY SEPARABLE FROM SAID INK FEED SECTION, SAID PEN SECTION ENGAGING SAID CARTRIDGE AND FORCING THE REAR OF SAID CARTRIDGE AGAINST SAID DEFORMING MEANS WHEREBY SAID BULGED PORTION IS DEFORMED AND FORCED INWARDLY OF SAID CARTRIDGE TO SLIGHTLY REDUCE THE VOLUME OF SAID CARTRIDGE AND TO FORCE ONLY A SMALL AMOUNT OF THE WRITING FLUID OUT OF SAID CARTRIDGE INTO SAID INK FEED SECTION. 